Outbreak of Diarrhea Caused by a Novel Cryptosporidium hominis Subtype During British Military Training in Kenya

Background

We report clinical, epidemiological, and laboratory features of a large diarrhea outbreak caused by a novel Cryptosporidium hominis subtype during British military training in Kenya between February and April 2022.

Methods

Data were collated from diarrhea cases, and fecal samples were analyzed on site using the multiplex polymerase chain reaction (PCR) BioFire FilmArray. Water was tested using Colilert kits (IDEXX, UK). DNA was extracted from feces for molecular characterization of Cryptosporidium A135, Lib13, ssu rRNA, and gp60 genes.

Results

One hundred seventy-two of 1200 (14.3%) personnel at risk developed diarrhea over 69 days. One hundred six primary fecal samples were tested, and 63/106 (59.4%; 95% CI, 0.49%-0.69%) were positive for Cryptosporidium spp. Thirty-eight had Cryptosporidium spp. alone, and 25 had Cryptosporidium spp. with ≥1 other pathogen. A further 27/106 (25.5%; 95% CI, 0.18%-0.35%) had non-Cryptosporidium pathogens only, and 16/106 (15.1%; 95% CI, 0.09%-0.23%) were negative. C. hominis was detected in 58/63 (92.1%) Cryptosporidium spp.-positive primary samples, but the others were not genotypable. Twenty-seven C. hominis specimens were subtypable; 1 was gp60 subtype IeA11G3T3, and 26 were an unusual subtype, ImA13G1 (GenBank accession OP699729), supporting epidemiological evidence suggesting a point source outbreak from contaminated swimming water. Diarrhea persisted for a mean (SD) of 7.6 (4.6) days in Cryptosporidium spp. cases compared with 2.3 (0.9) days in non-Cryptosporidium cases (P = .001).

Conclusions

Real-time multiplex PCR fecal testing was vital in managing this large cryptosporidiosis outbreak. The etiology of a rare C. hominis gp60 subtype emphasizes the need for more genotypic surveillance to identify widening host and geographic ranges of novel C. hominis subtypes.

Costimulation of γδTCR and TLR7/8 promotes Vδ2 T-cell antitumor activity by modulating mTOR pathway and APC function

Background

Gamma delta (γδ) T cells are attractive effector cells for cancer immunotherapy. Vδ2 T cells expanded by zoledronic acid (ZOL) are the most commonly used γδ T cells for adoptive cell therapy. However, adoptive transfer of the expanded Vδ2 T cells has limited clinical efficacy.

Methods

We developed a costimulation method for expansion of Vδ2 T cells in PBMCs by activating γδ T-cell receptor (γδTCR) and Toll-like receptor (TLR) 7/8 using isopentenyl pyrophosphate (IPP) and resiquimod, respectively, and tested the functional markers and antitumoral effects in vitro two-dimensional two-dimensional and three-dimensional spheroid models and in vivo models. Single-cell sequencing dataset analysis and reverse-phase protein array were employed for mechanistic studies.

Results

We find that Vδ2 T cells expanded by IPP plus resiquimod showed significantly increased cytotoxicity to tumor cells with lower programmed cell death protein 1 (PD-1) expression than Vδ2 T cells expanded by IPP or ZOL. Mechanistically, the costimulation enhanced the activation of the phosphatidylinositol 3-kinase (PI3K)–protein kinase B (PKB/Akt)–the mammalian target of rapamycin (mTOR) pathway and the TLR7/8–MyD88 pathway. Resiquimod stimulated Vδ2 T-cell expansion in both antigen presenting cell dependent and independent manners. In addition, resiquimod decreased the number of adherent inhibitory antigen-presenting cells (APCs) and suppressed the inhibitory function of APCs by decreasing PD-L1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression in these cells during in vitro Vδ2 T-cell expansion. Finally, we showed that human Vδ2 T cells can be expanded from PBMCs and spleen of humanized NSG mice using IPP plus resiquimod or ZOL, demonstrating that humanized mice are a promising preclinical model for studying human γδ T-cell development and function.

Conclusions

Vδ2 T cells expanded by IPP and resiquimod demonstrate improved anti-tumor function and have the potential to increase the efficacy of γδ T cell-based therapies.

Neural Crest-Like Stem Cell Transcriptome Analysis Identifies LPAR1 in Melanoma Progression and Therapy Resistance

Metastatic melanoma is challenging to clinically address. Although standard-of-care targeted therapy has high response rates in patients with BRAF-mutant melanoma, therapy relapse occurs in most cases. Intrinsically resistant melanoma cells drive therapy resistance and display molecular and biologic properties akin to neural crest-like stem cells (NCLSC) including high invasiveness, plasticity, and self-renewal capacity. The shared transcriptional programs and vulnerabilities between NCLSCs and cancer cells remains poorly understood. Here, we identify a developmental LPAR1-axis critical for NCLSC viability and melanoma cell survival. LPAR1 activity increased during progression and following acquisition of therapeutic resistance. Notably, genetic inhibition of LPAR1 potentiated BRAFi ± MEKi efficacy and ablated melanoma migration and invasion. Our data define LPAR1 as a new therapeutic target in melanoma and highlights the promise of dissecting stem cell-like pathways hijacked by tumor cells. SIGNIFICANCE: This study identifies an LPAR1-axis critical for melanoma invasion and intrinsic/acquired therapy resistance.

Tumor-infiltrating mast cells are associated with resistance to anti-PD-1 therapy

Anti-PD-1 therapy is used as a front-line treatment for many cancers, but mechanistic insight into this therapy resistance is still lacking. Here we generate a humanized (Hu)-mouse melanoma model by injecting fetal liver-derived CD34⁺ cells and implanting autologous thymus in immune-deficient NOD-scid IL2Rγ^null (NSG) mice. Reconstituted Hu-mice are challenged with HLA-matched melanomas and treated with anti-PD-1, which results in restricted tumor growth but not complete regression. Tumor RNA-seq, multiplexed imaging and immunohistology staining show high expression of chemokines, as well as recruitment of FOXP3⁺ Treg and mast cells, in selective tumor regions. Reduced HLA-class I expression and CD8⁺/Granz B⁺ T cells homeostasis are observed in tumor regions where FOXP3⁺ Treg and mast cells co-localize, with such features associated with resistance to anti-PD-1 treatment. Combining anti-PD-1 with sunitinib or imatinib results in the depletion of mast cells and complete regression of tumors. Our results thus implicate mast cell depletion for improving the efficacy of anti-PD-1 therapy.

Immune checkpoint therapies (ICT) are promising for treating various cancers, but response rates vary. Here the authors show, in mouse models, that tumor-infiltrating mast cells colocalize with regulatory T cells, coincide with local reduction of MHC-I and CD8 T cells, and is associated with resistance to ICT, which can be reversed by c-kit inhibitor treatment.

Abstract A26: Humanized mouse model: A model to understand mechanisms of immune non-responsiveness to immune checkpoint inhibitors in melanoma

Immune checkpoint inhibitor therapy (anti-CTLA4 or anti-PD1 antibodies) is rapidly emerging as a front-line treatment option for many solid tumors. However, only a third of melanoma patients respond to immune checkpoint blockade. Currently available mouse xenograft and transgenic models have many shortcomings and are unable to address the basis of therapy resistance and immune nonresponsiveness that are observed in patients. Thus, there is an urgent need to establish an in vivo model with a human immune microenvironment that can address issues of therapy resistance. Our laboratory has developed a novel humanized mouse melanoma model. Immunodeficient NSG mice were reconstituted with human CD34+ cells and after 8-12 weeks, mice are fully reconstituted with human innate (monocyte/myeloid lineage cells, dendritic cells and NK cells) and adaptive (T and B cells) immune cells. Humanized mice were then challenged with HLA-matched melanoma cells, and the functional ability of human immune cells to restrict tumor growth was monitored. Delayed tumor growth was observed in humanized mice, indicating in vivo sensitization of human immune cells to melanoma. This was confirmed by in vitro demonstration of human lymphocytes from tumor-bearing mice showing enhanced cytokine expression after stimulation with melanoma antigen peptides. In therapy studies, tumor-bearing humanized mice treated with anti-PD-1 showed restricted tumor growth. Anti-PD-1 therapy resulted in enhanced infiltration of T cells that correlated with tumor response. MassCyTOF studies were performed using a panel of immune markers to understand the mechanism of therapy nonresponsiveness in some tumors. Downmodulation of HLA-class I molecules and increased presence of FOXP3+ cells in the tumor region were seen. Our results suggest that humanized mouse melanoma model can be explored further to understand the causes of therapy resistance and immune nonresponsiveness.

Citation Format: Rajasekharan Somasundaram, Anastasia Samarkina, Thomas Connelly, Robin Choi, Hedy Choi, Kar Muthumani, Xiaowei Xu, Klaus Kaestner, Meenhard Herlyn. Humanized mouse model: A model to understand mechanisms of immune non-responsiveness to immune checkpoint inhibitors in melanoma [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr A26.

Abstract PR18: Comparative screening of skin-derived NCSCs, melanocytes, and melanoma developmental programs reveals LPAR1 in MAPKi resistance

Despite the high efficacy of BRAFi/MEKi in BRAF-MT melanomas, resistance arises in the majority of cases. Melanoma hijacks developmental pathways that drive aggressiveness; however, gene signatures shared by melanocyte progenitor cells and melanoma cells remain poorly understood. Here, we define common dependencies in neural crest stem cells (NCSCs) and melanoma cells not present in melanocytes through computational transcriptome analyses and targeted siRNA screens against shared developmental genes. Secondary validation coupled with Ingenuity Pathway Analysis identified the LPAR1-RAPGEF5-RAP1A axis as the top pathway critical for stem cell maintenance and melanoma aggressiveness. Genome-wide gene expression data in the CCLE demonstrates LPAR1 correlates with the MITFlo/AXLhi intrinsic MAPKi resistance signature. In agreement, LPAR1 is elevated in MAPKi-resistant PDX models, and in a subset of post-treatment tumor biopsies from patients who relapsed on MAPKi, relative to respective paired pretreatment biopsies. Melanocytes and fibroblasts express low levels of LPAR1 and are not sensitive to LPAR1i. In contrast, genetic silencing of LPAR1 and pharmacologic inhibition of LPAR1 with HA130, an upstream LPAR1 inhibitor, triggers cell cycle arrest and antitumor activity in MAPKi-resistant cells in vivo. Mechanistically, genetic and pharmacologic targeting of LPAR1 downregulates genes involved in the PI3K/mTOR and Hippo/YAP. Concurrent depletion of YAP and S6K cells significantly impairs melanoma viability relative to knockdown of YAP or S6K alone, suggesting that Hippo/YAP and mTOR/S6K pathways are main downstream effectors of LPAR1 signaling in melanoma. Our data identify novel pathways responsible for the escape of BRAF mutant melanoma from MAPKi therapy, and our hypothesis is that concurrent BRAFi/MEKi/LPAR1i may have therapeutic efficacy.

This abstract is also being presented as Poster B02.

Citation Format: Vito W. Rebecca, Jianglan Liu, Thomas Connelly, Keith Flaherty, Ze’ev Ronai, Meenhard Herlyn. Comparative screening of skin-derived NCSCs, melanocytes, and melanoma developmental programs reveals LPAR1 in MAPKi resistance [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR18.

Education in skin cancer management--assessing knowledge and safety

BACKGROUND

General practitioners manage the majority of skin cancers in Australia. There are a range of training opportunities for, and certifications in, skin cancer management.

METHOD

Between 15 June and 25 June 2008, an online examination was placed on the Australasian College of Skin Cancer Medicine website. Two hundred and forty-five college affiliated doctors were invited by email to complete the examination. Thirty questions were asked pertaining to the management of a hypothetical case study including melanoma, basal cell carcinoma and squamous cell carcinoma.

RESULTS

Of 187 doctors who had an active responding email address, 140 (75%) took the examination. From a possible score of 100, the mean score was 84 +/- 16. The median score was 80.

DISCUSSION

Some trends emerged. Longer and more detailed training programs correlated with better subsequent knowledge retention and safety. Two days of training may not make doctors sufficiently safe in skin cancer management; it appeared to improved knowledge, but not to a point where unsafe practice was eliminated.

Olfactory dysfunction in degenerative ataxias

Several lines of evidence suggest that the cerebellum may play a role in higher-order olfactory processing. In this study, we administered the University of Pennsylvania Smell Identification Test (UPSIT), a standardised test of olfactory function, to patients with ataxias primarily due to cerebellar pathology (spinocerebellar ataxias and related disorders) and to patients with Friedreich ataxia, an ataxia associated mainly with loss of afferent cerebellar pathways. UPSIT scores were slightly lower in both patient groups than in the control subjects, but no differences were noted between the scores of the Friedreich and the other ataxia patients. Within the Friedreich ataxia group, the smell test scores did not correlate with the number of pathologic GAA repeats (a marker of genetic severity), disease duration, or categorical ambulatory ability. UPSIT scores did not correlate with disease duration, although they correlated marginally with ambulatory status in the patients with cerebellar pathology. This study suggests that olfactory dysfunction may be a subtle clinical component of degenerative ataxias, in concordance with the hypothesis that the cerebellum or its afferents plays some role in central olfactory processing.

Relationship between peripheral intravenous catheter Dwell time and the development of phlebitis and infiltration

The purpose of this study was to evaluate whether lengthening the dwell time of peripheral i.v. catheters from 72 hours to 144 hours resulted in increased rates of phlebitis and/or infiltration. The study was conducted in medical/surgical units at a 110-bed teaching hospital with an i.v. team. Kaplan-Meier estimates of the success and failure and conditional failure probabilities were calculated for phlebitis and infiltration scores. Log rank tests were used to test for an association between the covariates and the time until failure. Drug irritation was the most significant predictor of phlebitis and infiltration rates in this study. The total difference in the estimated failure rates for the catheter lasting 6 days versus a new catheter inserted for another 3 days is 1.3%. Because the conditional failure probability estimates for days 4, 5, and 6 are slightly higher than for days 1, 2, and 3, consideration may be given to extending the dwell time of a peripheral i.v. catheter beyond 72 hours under certain circumstances.

Basic organizational considerations for interdisciplinary education development in the health sciences

In this paper, the author reviews the organizational problems associated with developing an interdisciplinary educational experience for health science students. Within the paper, ten basic issues are reviewed and commented upon. The paper also attempts to highlight some philosophical issues related to the interdisciplinary approach to education as well.

The use of ultra-low-dose aprotinin to reduce blood loss in cardiac surgery

One hundred patients due to undergo primary cardiac surgery were prospectively randomized to receive aprotinin or placebo. In the aprotinin group, 250,000 kallikrein inhibitory units (KIU) of aprotinin were added to the cardiopulmonary bypass prime solution. A further 250,000 KIU of aprotinin were infused intravenously over 30 minutes immediately before the start of cardiopulmonary bypass. The control group received 0.9% saline in equal volumes at identical times. The study was designed to have a 90% chance of demonstrating a 30% reduction in blood loss. No significant differences were found between the two groups. The median blood loss in the aprotinin group was 750 mL (interquartile range 556 to 1025 mL, 95% confidence interval 600 to 800 mL). In the control group, the median blood loss was also 750 mL (interquartile range 500 to 988 mL, 95% confidence interval 625 to 925 mL). In the aprotinin group, 12 patients received postoperative autotransfusion of shed mediastinal blood of median volume of 665 mL (interquartile range 500 to 925 mL, 95% confidence interval 450 to 1000 mL). In the control group, 14 patients received postoperative autotransfusion of mediastinal blood of median volume of 663 mL (interquartile range 600 to 800 mL, 95% confidence interval 600 to 700 mL). Five patients in the aprotinin group and seven patients in the control group required postoperative homologous blood transfusion. Reassessment of inclusion criteria showed a 19% reduction in blood loss in patients undergoing only aortocoronary bypass receiving aprotinin compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Removal of Mg2+ inhibition of cardiac ryanodine receptor by palmitoyl coenzyme A

45Ca2+ fluxes and planar bilayer recordings indicated that the fatty acid metabolite palmitoyl coenzyme A, but not free coenzyme A or palmitic acid, stimulated the cardiac ryanodine receptor channel of pig heart sarcoplasmic reticulum. Palmitoyl CoA reactivated channels inhibited by concentrations of cytoplasmic free Mg2+ in the physiological range. Reactivation by palmitoyl CoA in the presence of Mg2+ was stimulated by myoplasmic free Ca2+ in the micromolar range. Acyl coenzyme A derivatives may be utilized by cardiac muscle cells to compensate for the severe Mg2+ inhibition of ryanodine receptors which would otherwise leave Ca2+ stores unresponsive to Ca2+ and to other cytosolic ligands involved in signal transduction.

Allied health: economic, social, or service instrument?

Allied health as a concept has been studied by economists, educators, and others, but rarely has it been dealt with as an historical and social phenomenon. Examining the development of what is called allied health, one can see a picture of how the American health care system has evolved and, perhaps, a glimmer of its future. This article looks at some of the economical, educational, social, and public policy issues from which allied health has emerged and provides a perspective on where it could lead.

Continuing education: an attitudinal survey of physical therapists

A descriptive study of 903 physical therapists located primarily in southeastern United States was undertaken to determine their attitudes toward continuing education and the types of course offerings they desired. A majority of physical therapists kept themselves up-to-date in professional practice, mainly through discussion with colleagues, study groups, and inservice training sessions. The continuing education courses they preferred were comparatively recent topics in physical therapy education--such as musculoskeletal assessment and mobilization--specific neurophysiological approaches to treatment of adults and children, and administration. The study also revealed the preferred schedule, length, type, and cost of continuing education courses, as well as the amount of advance notice preferred and willingness to complete preassigned readings. The main problem that respondents had in participating in continuing education was that courses did not fit into their schedules. A majority of respondents favored mandatory continuing education for relicensure.

Continuing education in allied health: the state of the art

This paper reports the results of a study on continuing education in 61 allied units. It was conducted to determine the current state of the art of continuing education activity in allied health units. It was found that while continuing education activities are increasing in allied health, there is not a strong administrative commitment being made to internalize continuing education as a function of education.

Interdisciplinary education for health science students in the rural home health agency. Kentucky January

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